Two episodes of urinary retention occurred in a 15-year-old male following administration of clomipramine given for obsessive-compulsive disorder. Improvement of behavioral symptoms along with side effects was clearly correlated with clomipramine dosage. Severity of side effects, and their resistance to bethanechol and to phenoxybenzamine, necessitated a complete withdrawal of clomipramine. This case demonstrates that clomipramine-induced urinary retention is not limited to older individuals. Possible involvement of noncholinergic and nonadrenergic mechanisms in this adverse drug reaction is suggested.